I have a 1997 Nissan Pathfinder SE in which the monitors will not settle. The problem started with the knock sensor in which we replaced it and everything seem fine until then EGR flow valve came up, boom that was fix. Then out of nowhere the MAP/BARO solenoid valve came up, turns out that the hoses were switch and as well one was crack. So after taking it to the mechanic I drove back home (5 miles) in which the only two monitors I have pending are the Oxygen and the Catalyst Monitors pending in order to be able to pass smog. I drove to the market in which was 7 miles away and then to the market in which was 2 miles away and back home. After that I let the car cool down for 6 hours in which then I drove it to work in which is 6 miles away and the monitors still showed pending. I let the car cool down for 7 hours and finally drove it about 80 miles non-stop but the monitors still were blinking on my OBII scanner........what else can I do in order to have these monitors settle in? Before it was the Heat Catalyst Monitor, EGR monitor, EVAP monitor, Oxygen Sensor Heater monitor, Oxygen monitor....after the map/baro and EGR valve were fixed the only two pending now is the Oxygen and the Catalyst.....any suggestions?

You need to put it through a specific driving pattern. Those short drives and cool downs don't do anything for it.

See page EC-40 and EC-41 in the 97 FSM:
http://www.nicoclub.com/FSM/Pathfinder/ ... der/ec.pdf

The driving pattern is described on the bottom portion of the chart on EC-40:
Start engine, let it idle, accelerate to 53-60, stay there for 10 mins, do several stop/go from 0 to 30-35, resume at 53-60, shut engine off. You can do other things in between (stop/go/diff speeds), but keep the engine on. For instance, you can go 70 if you want, but only time spent between 53-60 counts for the pattern.

From the chart you can also see which part of the pattern readies each system. But if you treat it as a linear process, you'll hit all of them in one drive.

It's a wonky process, but it works, having had to do it several times on different Nissans prior to emissions tests (post ECU resets), including my 04 PF. I recommend a long stretch of highway, some frontage roads, a co-pilot, a printout of the chart, and a stop-watch.

Hawairish wrote:You need to put it through a specific driving pattern. Those short drives and cool downs don't do anything for it.

See page EC-40 and EC-41 in the 97 FSM:
http://www.nicoclub.com/FSM/Pathfinder/ ... der/ec.pdf

The driving pattern is described on the bottom portion of the chart on EC-40:
Start engine, let it idle, accelerate to 53-60, stay there for 10 mins, do several stop/go from 0 to 30-35, resume at 53-60, shut engine off. You can do other things in between (stop/go/diff speeds), but keep the engine on. For instance, you can go 70 if you want, but only time spent between 53-60 counts for the pattern.

From the chart you can also see which part of the pattern readies each system. But if you treat it as a linear process, you'll hit all of them in one drive.

It's a wonky process, but it works, having had to do it several times on different Nissans prior to emissions tests (post ECU resets), including my 04 PF. I recommend a long stretch of highway, some frontage roads, a co-pilot, a printout of the chart, and a stop-watch.

I did the stright linear shot for 70mph @ 40 miles distance, I heard GM driving pattern in which it involves the stop and go also overload the electrical by turning on the a/c and etc

The Nissan process is pretty specific, but since this is an emissions test, it shouldn't have any requirements for an electrical load. The patterns are both speed and time dependent.

And by linear process, I mean a step-by-step and not just a static speed for a given distance. The reason that some monitors are ready while others are not is because some monitors have less readiness parameters than others. The two you're missing are the ones that require the more attention to the pattern, but running the full pattern will be sure to satisfy all monitors.

For what it's worth, I just completed a long road trip during which I reset the ECU a few times (including while driving). I was able to make-ready all of the sensors without doing the driving pattern, and while at highway speeds. So maybe there's hope for you, but you may still want to try a sub-70 speed for some period.

The drive pattern is set to resemble the pattern of the IM240 test used in states that do emission testings on a dyno. It's not a "you have to do it exactly as the diagram states" type of test, but the ECM is looking for specific things during the overall course of the drive cycle for testing purposes.

Yep, no argument there about a particular order. I was only advocating what the FSM describes so that the OP has a sure-fire way to make-ready those sensors. I've been in both situations where, facing emissions testing, drove it randomly for some 100 miles, and drove it according to the FSM pattern. In no case did the random drive work for me, but in all cases the pattern worked.

However, going 70 mph for an extended period is outside of what the FSM describes as satisfying any of the 4 patterns, each of which satisfies one or more readiness tests. That's the only point I was originally making. But having seen it first hand, and in some cases where some events never occurred post ECU reset, I was surprised to see that all sensors on my truck were ready. In one particular case, I had never even started or stopped the truck...it was already running, at 65+ mph when reset, and I confirmed it before turning the truck off. That shouldn't satisfy all readiness tests according to the FSM, but I can tell you that it did in my case.

I would usually start the vehicle cold, let it idle for 5 mins until it reached normal operating temperature, then take it for a 20 minute ride, including some "around town" driving and some highway cruising. Most of the time it worked, but it was very hard to get the EGR test to pass in cold weather, I found.

Hawairish wrote:The Nissan process is pretty specific, but since this is an emissions test, it shouldn't have any requirements for an electrical load. The patterns are both speed and time dependent.

And by linear process, I mean a step-by-step and not just a static speed for a given distance. The reason that some monitors are ready while others are not is because some monitors have less readiness parameters than others. The two you're missing are the ones that require the more attention to the pattern, but running the full pattern will be sure to satisfy all monitors.

I was able to get the Oxygen monitor stabilized now I am waiting for the Catalyst to get programmed. The first few 10 minutes the monitor of the Oxygen was in, Catalysis was the one that I was not able to get it

smj999smj wrote:I would usually start the vehicle cold, let it idle for 5 mins until it reached normal operating temperature, then take it for a 20 minute ride, including some "around town" driving and some highway cruising. Most of the time it worked, but it was very hard to get the EGR test to pass in cold weather, I found.

I let it idle for 5 minutes and took it for a spin. The oxygen monitor is settle just need the catalysis to settle in. I see that at the end of the chart it says that the engine needs to be stop but for how long?

If it doesn't say, I can't tell you. As I mentioned, it's not an exact process, but just a chart to demonstrate what the ECM is generally looking for to complete the system readiness test.

smj999smj wrote:If it doesn't say, I can't tell you. As I mentioned, it's not an exact process, but just a chart to demonstrate what the ECM is generally looking for to complete the system readiness test.

true that, my mistake today was that I cannot complete the 4th phase in which was traffic so the pedal was off and on